in the NS file (which is in TCL is derived from the node class). For
example.

set nodea    [$ns node]
set bridge1  [$ns bridge]
set bridge2  [$ns bridge]
set nodec    [$ns node]

set link0 [$ns duplex-link $nodea $bridge1 * 0ms DropTail]
set link1 [$ns duplex-link $nodec $bridge1 * 0ms DropTail]

With changes to the mapper, this allows the mapper to map multiple
bridge nodes to a single physical node, like we do for delay nodes
when there are enough interfaces.

As a convenience to users, now named_setup adds CNAMES for the
additional multiple mapped nodes.